Taurine has been suggested as a component in animal feed, see U.S. Pat. No. 3,636,195. Taurine has also been suggested for incorporation into synthetic infant formulas, see G. E. Gaull U.S. Pat. No. 4,303,692.
Taurine (2-aminoethanesulfonic acid, NH.sub.2 CH.sub.2 CH.sub.2 SO.sub.3 H) is a beta-sulfonic acid present in high concentrations in animal cells. Taurine and its related compounds, such as hypotaurine (2-aminoethanesulfinic acid) and isethionic acid (2-hydroxyethanesulfonic acid) are formed in animal tissue and vary in concentration from species to species and among tissues. Little, if any, taurine is found in plants.
Additionally, platelets and lymphocytes are found to have present large concentrations of taurine, ranging up to about 50% of the total pool of free amino acids present in these cells. The physiological function of taurine remains unclear, although it is clear that it is an important amino acid for maximal cell viability and homeostasis. Additionally, at least one investigator has termed taurine a "conditionally essential nutrient" meaning that, although the nutrient is not essential for normal subjects, certain individuals, having lost the ability to conserve the compound or having increased requirements due to illness or for other reasons, must supplement their diets with taurine to maintain normal health. Chipponi et al, Am. J. Clin. Nut., 35, (May 1982), pp. 1112-1116; Jacobsen and Smith, Phys. Rev. v. 48, No. 2, (April 1968), pp. 424-511.
The cells of many species possess considerable ability to synthesize taurine, although this is not the case with primates, including man. Certain animals including primates and man have very limited ability to synthesize the amino acid, and rely on diet to maintain taurine stores.
Human B-lymphoblastoid cells take up taurine present in physiological concentrations in plasma, using an active uptake system. These same cells take up taurine when cultured in media supplemented with serum, and show progressive depletion of taurine when cultivated in chemically defined, taurine free media.
Taurine exhibits a positive effect on the number of viable cells in a culture when added to a taurine free medium used in such a culture. Evidence is available which supports the hypothesis that taurine mediates protective action on cell membranes which lead to an increase in cell viability. Huxtable and Bressler, Biochem et Biophys. Acta., 323 (1973), pp. 573-583.
Retinols, the major components of vitamin A, and the related compounds, retinoids, are well known as inhibitors of cell growth. These compounds interact directly with membranes causing increases in permeability and fluidity, and destabilize biological membranes, Stillwell and Bryant, Biochim et Biophys. Acta, 731 (1983) 483-486. This results in hemolysis in erythrocytes, and in increased enzyme secretion in lysosomes. Additionally, when retinols are incorporated into lipid bilayers of liposomes, these are made more permeable to cations and to larger molecules, such as glycine, lysine and glucose. The increase in permeability is often accompanied by decreases in phase temperatures of the liposomes, as well as electrical resistance of the membranes.
Ascorbic acid, i.e. vitamin C, and the related ascorbates, in systems with iron compounds, are known to induce lipid peroxidation of cell membranes, see, e.g. Lewis, Biochem. Pharm. v. 33, No. 11, pp. 1705-14 (1984). The damage that results from this peroxidation is often accompanied by increased membrane permeability, and enhanced water accumulation. When either retinols or iron-ascorbate systems are present, cell viability is decreased due to membrane interference caused by the presence of these, Stillwell and Bryant, op. Cit.; Lewis, op. Cit.
Each of these, i.e., vitamin A (retinol), vitamin C (ascorbic acid or ascorbate), and iron compounds is a necessary nutrient for humans. Hence, removal of these substances from the diet is not possible. In fact, each of these substances may be taken not only through natural occurrence in comestibles, but also through vitamin and mineral nutritional supplements. These supplements are available in a variety of formulations, and often contain well in excess of the amount of each substance necessary for proper nutrition, even when suggested doses are taken. Many who take vitamin supplements, however, believe that increased consumption of these supplements will result in increased beneficial effects. Actually, such increased consumption may lead to increased risk of cell damage, as set forth herein.
Taurine and its physiologically acceptable derivatives have been shown to have a positive effect on cell viability, see, e.g. Alverez & Storey, Biol. Reprod., 29, 548-555 (1983). Evidence supports the view that taurine mediates a protective effect on cell membranes. Zinc has been shown to exhibit a protective effect on cell membranes as well.
Vitamin E, or tocopherol, is known as having positive effects in counteracting membrane destabilizing actions of retinoids, Stillwell & Bryant, op. Cit.; I. Gery, Inv. Ophthal & Vis. Sci. v. 19 (December 1980) pp. 751-759.
Hence, it is one object of this invention to prepare vitamin compositions having improved nutritional properties.
It is another object of this invention to provide comestibles or food compositions having improved nutritional properties.
How these, as well as other objects of this invention are realized, will be made clear in light of the following disclosure.